amino acid

noun

: an amphoteric organic acid containing the amino group NH₂

especially : any of the various amino acids having the amino group in the alpha position that are the chief components of proteins and are synthesized by living cells or are obtained as essential components of the diet

Examples of amino acid in a Sentence

Recent Examples on the Web

Whey protein contains branched-chain amino acids, which are beneficial for muscle growth and recovery. —Lana Barhum, Verywell Health, 12 July 2025

In a lot of cases, frizziness is caused when the hair is lacking moisture, so this cream features a blend of keratin amino acids and rice protein to address issues of dryness from inside the strands. —Danielle Jackson, Glamour, 9 July 2025

These amino acids may protect against the development of atherosclerosis, or the thickening or hardening of the arteries caused by a buildup of plaque. —Jillian Kubala, Health, 8 July 2025

Protein rich, these trail MVPs provide all nine amino acids and are easy to throw in the top of any hiking pack. —Kade Krichko, Outside Online, 4 July 2025

Word History

First Known Use

1897, in the meaning defined above

Rhymes for amino acid

• antacid
• placid

Kids Definition

amino acid

noun

ami·​no acid

ə-ˈmē-nō-

: any of numerous acids that include some which are the building blocks of proteins and are made by living cells from simpler compounds or are obtained in the diet

Medical Definition

amino acid

noun

: an amphoteric organic acid containing the amino group NH₂

especially : alpha-amino acid